! { dg-do run }

function dotprod_ref (B, C, N) result (sum)
  implicit none
  real :: B(N), C(N), sum
  integer :: N, i
  sum = 0.0e0
  do i = 1, N
    sum = sum + B(i) * C(i)
  end do
end function

function dotprod (B, C, N) result(sum)
  real :: B(N), C(N), sum
  integer :: N, i
  sum = 0.0e0
  !$omp target teams map(to: B, C) map(tofrom: sum) &
  !$omp& reduction(+:sum)
    !$omp distribute parallel do reduction(+:sum)
    do i = 1, N
      sum = sum + B(i) * C(i)
    end do
  !$omp end target teams
end function

subroutine init (B, C, N)
  real :: B(N), C(N)
  integer :: N, i
  do i = 1, N
    B(i) = 0.0001 * i
    C(i) = 0.000001 * i * i
  end do
end subroutine

subroutine check (a, b)
  real :: a, b, err
  real, parameter :: EPS = 0.0001
  if (b == 0.0) then
    err = a
  else if (a == 0.0) then
    err = b
  else
    err = (a - b) / b
  end if
  if (err > EPS .or. err < -EPS) stop 1
end subroutine

program e_54_3
  integer :: n
  real :: ref, d
  real, pointer, dimension(:) :: B, C
  n = 1024 * 1024
  allocate (B(n), C(n))
  call init (B, C, n)
  ref = dotprod_ref (B, C, n)
  d = dotprod (B, C, n)
  call check (ref, d)
  deallocate (B, C)
end program
